A marked rise in rabbit project development activities
throughout the developing countries has been observed within the
past 10 years. This global response may be attributable to an
increased awareness of the potential of small-scale rabbit
production for the world's majority of subsistence rural and
peri-urban inhabitants. There is a tremendous need for
descriptive data of rabbit populations. Fortunately, relevant
economic, nutritional and sociological parameters associated with
rabbit production are now becoming available from certain
developing countries, such as China, Egypt, Indonesia, Mexico,
Nigeria and Tanzania. Available technical information from
developed countries in many instances is not appropriate to
locally specific conditions represented in many developing
countries. Applied research conducted in developing countries on
vital aspects of rabbit production: breeding and genetics,
disease control, economics, housing systems, management,
nutrition and reproduction, is urgently needed in order to ensure
a high potential success rate for rabbit development projects, in
terms of achieving favorable economic, nutritional and
sociological impact.

It is generally regarded that rabbits were first introduced
into many developing countries by colonial settlers and
missionaries. Conventional captive meat rabbit production largely
represents, therefore, a relatively recently introduced small
livestock activity in many countries in the Third World.

While applied and basic rabbit research conducted in developed
countries has yielded numerous reports in the scientific
literature, research reports on the various production aspects of
rabbit production are limited from the lesser developed countries
(LDC's). Results of studies from non-LDC's are generally not
appropriate for tropical production systems because environmental
factors (eg: climate, diet, housing and management) and genetic
stocks relate only to what is typically found in temperate
regions.

In order for rabbit development projects in LDC's to be
successful, it is imperative that more research be done whereby
locally specific conditions, such as economic, social, breeding
stock and forage resources, are taken into account.

The purpose of this paper is to address local technology
issues and suggest appropriate research which could advance the
role of the rabbit as a beneficial agricultural species.

Suitable breeds and selection practices

The progenitor of the domestic rabbit (Oryctolagus
cuniculus) is believed to have evolved in the Mediterranean
region, extending later into the Middle East and North Africa.
Beyond this restricted global area, the rabbit may be truly
considered non-indigenous. In general, two types of rabbit can be
found throughout the developing world: local strains and
"improved" exotic breeds. Local strains, such as the
Criollo in Latin America, the Japanese Large White and Sichuan
White in Asia, and the Baladi in the Near East and North Africa,
may have existed in these geographic regions for decades, even
centuries. In most cases they represent an introduced food
species, not truly indigenous. For the local strains it is
possible that a marked extent of genetic adaptation to a unique
environment has gradually occurred over generation time. Such
valuable germplasm resources should be properly conserved through
government policy. In cases where local strains are in danger of
extinction, immediate efforts should be made to preserve such
genetic stocks (Lukefahr 1988a).

One highly typical observation of many local strains involves
the apparent small body size and low productivity. This may be
explained on genetic grounds by: (1) original introduction of
small, lowly productive stock; (2) natural selection and (3)
absence of artificial selection for increased productivity, or
some combination thereof. The first point is straightforward,
while the second point implies natural selective advantage for
small body size and/or decreased productivity to genetically
conform to an adverse environment. Absence of artificial
selection refers to a basically non-existent selection program
for increased meat producing capacity. Other operative factors,
of both genetic and environmental origin, may be involved.

A second general impression is the seemingly wide genetic
variability, detected at the phenotypic level, within many local
rabbit strains for such characters as coat color, body
conformation and size and production. In Cameroon, one local
strain expressed some eighteen different coat colors and/or
patterns, as observed by the first author, which perhaps reflect
the original crossings of several distinct rabbit breeds prior to
or following initial introduction to the country. In addition,
the presence of important levels of heterosis, favorably
affecting performances, may potentially exist, especially where
the local strain represents a composite of several original
breeds. This specific genetic effect may enhance greater
physiological capacity for successful environmental adaptation.
Furthermore, heritability levels could, in effect, be
significantly increased, according to genetic theory.

While reports to confirm such hypotheses are not conclusively
available in the literature, if such wide genetic variability
indeed exists within certain local strains for production traits,
there would appear to be ample opportunity for achieving
impressive genetic progress through applied selection.

Simultaneous genetic improvement for both local adaptation and
production characteristics could conceivably be set as the
primary breeding goal for government breeding stations and large
private rabbit farms. Table 1 provides pertinent information on
reported heritability estimates for various production traits in
rabbits.

Selection emphasis should be applied to traits of moderate to
high heritability, such as individual growth and carcass-related
traits. For lowly heritable traits, such as litter size and
survival, baseline culling levels (independent culling technique)
for low average record productivity should be established.

Unfortunately, a widely observed practice is the
indiscriminate crossing of breeds on the unfounded notion that
local breeds are genetically inferior. A serious consequence of
this practice is the possible loss of local germ-plasm and
lowered productivity of imported breeds due to unsuccessful
environmental adaptation. In probably all cases, breed evaluation
tests (local vs exotic stocks) should be conducted prior
to widespread distribution.

Numerous exotic breeds of rabbit have rather recently been
introduced into many developing countries. Perhaps the most
common imported breeds are the Californian, the Chinchilla, the
Flemish Giant and the New Zealand White. Although some decline in
fertility has been observed, in general, many exotic breeds of
rabbit have been observed to perform relatively well under a
diversity of environmental conditions (IFS 1978; Campos et al
1980; Carregal 1980; Damodar and Jatkar 1985), as long as proper
feeding, housing, management and health measures were
consistently practiced. For the purpose of breed comparisons
across broad regions of the developing world, limited data on
only two breeds - Californian and New Zealand White - are
reported in the scientific literature. Both commercial meat
breeds would appear to be potentially suitable for most
environments. More basic research is needed in order to make
major recommendations as to the appropriateness of certain breeds
in specific environments. Currently no breed of rabbit can be
universally recommended.

A popular animal breeding practice used in many developing
countries is simple upgrading. This involves successive
generations of matings of an exotic breed to the locally
available strain to increase the proportion of exotic breed
inheritance. The early generation crosses may perform better than
the local parental strain, in terms of annual meat productivity.
For this reason some rabbit projects prefer to distribute
crossbred stock to farmers.

Table 1: Heritabilities
of production traits in rabbits

Trait

Heritability

Source

Fertility
and litter size

- Litter size
born alive

2.1

Lampo and Van
Den Broeck 1975

3.0

Rollins et
al 1963

- Litter size
weaned:

28 days

15.0

Matheron and
Poujardieu 1984

56 days

0.0

Rollins et
al 1963

Disease-related

- Enteritis
and Pneumonia deaths

. to 56 days
of age

12.0

Rollins and
Casady 1967

- Survival to
56 days

6.0

Harvey et
al 1961

Maternal
production-related

- Maternal
behavior (nest building)

24.0

Berovides and
Fernandez 1982

- Milk
production

31.0

Patras 1985

45.5

Randi and
Scossiroli 1980

Growth-litter
records

- Average
weight per rabbit:

21 days

36.0

Leplege 1970

56 days

65.0

Leplege 1970

- Total
litter weight:

56 days

0.0

Rollins et
al 1963

56 days

22.0

Lukefahr 1982

-- adjusted
for litter size

69.4

Lukefahr 1982

Growth-individual
records

- Body
weight:

1 day

40.0

Bogdan 1970

30 days

17.0

Rouvier 1981

56 days

22.6

Mostageer et
al 1970

60 days

54.0

Patras 1985

- Rate of
gain:

30-70 days

44.0

Rouvier 1981

- Feed
consumption:

30-70 days

32.0

Vrillon et
al 1979

- Feed
efficiency:

28-77 days

34.0

Baselga et
al 1982

- Loin width:

56 days

60.0

Bogdan 1970

Carcass-related

- Dressing
percentage

60.0

Fl'ak (1978)

- Hot carcass
weight:

70 days

61.0

Poujardieu et
al 1974

70 days

36.0

Rouvier 1981

- Meat:bone
ratio (hind-leg)

49.7

Varewyck et
al 1986

- Weight of
hind-leg meat

60.0

Fl'ak 1978

* Source: Complete references
cited by Lukefahr (1988b).

From a genetic standpoint, exceptional crossbred productivity, if
real, may be attributable to favorable additive and maternal
breed effects, heterosis, and/or other more complex forms of gene
action. Such improved varieties may be developed into new
synthetic breeds of rabbit where capable genetic expertise and
related resources are available. To date, an improved breed of
rabbit genetically developed under tropical conditions does not
yet exist. Research in this promising area is strongly warranted.
More sophisticated systems of crossbreeding, such as rotational
and terminal crossing, while being more widely practiced in
commercial operations in developed nations, are not presently
feasible in many instances in developing countries. Furthermore,
such advanced systems entail various sectors in the commercial
rabbit industry, such as seed- stock and hybrid stock companies,
which do not generally exist in developing countries.

In terms of practical stock selection, farmers may avoid
undesired inbreeding through routine exchange of herd bucks with
other farmers. Selection of offspring from consistently
productive and healthy parental stock is recommended to farmers.
This involves the regular keeping of basic pedigree and
production records. In addition, simple financial records should
be maintained.

The current demand among farmers and other project recipients
for quality breeding stock in an LDC may be great. In some cases,
national or regional rabbit breeding centers (governmental and
private) presently provide this valuable service in several
developing countries.

Feeds and feeding under tropical conditions

One of the advantages of rabbit production in tropical
countries is that rabbits can be fed forages and agricultural
by-products that are not suitable for human consumption. In
general, if feedstuffs are available that are suitable for
poultry production, it is more efficient to produce poultry with
these feeds than rabbits. The niche that rabbit production can
occupy is in the utilization of fibrous by-products that are not
useful for poultry, as well as swine, and forages that may be
available in insufficient quantities for raising ruminants. When
these feeds make up the bulk of the diet, the use of a small
quantity of concentrate feed to improve performance can be
justified.

The growth performance of rabbits in studies reported from
tropical countries is generally in the range of 10-20 g per day,
in contrast to 35-40 g per day commonly observed in temperate
regions. Probably a number of factors, including heat stress, are
involved as well as diet. An interesting study would be to
determine the production of rabbits of the same breed in various
tropical locations when fed the same diet as used in American or
European studies, to determine the degree to which the poorer
performance can be attributed to environment.

Only limited data are available on the nutritional value of
tropical feeds for rabbits, and even less data exist on feeding
systems and programs. The most extensive compilation of
nutritional data on rabbit feeds is that of Raharjo (1987), who
evaluated a number of Indonesian forages and agricultural
by-products. Ayoade et al (1985) reported on the
composition of a number of African forages with potential as
rabbit feeds. In general, the tropical legume forages are higher
in protein and lower in fibre than the tropical grasses, and are
much more digestible (Tables 2 and 3).

It is clear from these data that careful selection of forages is
an essential first step in developing suitable feeding systems.
In Indonesia, for example, producers have had very poor success
with the use of Setaria spp. as rabbit forage, even though
the grass appears visually to be a suitable feed. The explanation
for the poor results is that it is almost completely indigestible
(Table 3). Tropical grasses have a cellular structure that
resists degradation in the digestive tract; they have a high
content of poorly digested constituents such as vascular tissue,
parenchyma bundle sheaths and epidermis, and a low content of the
more readily digested mesophyll cells. Much more data of the type
shown in Tables 2 and 3 are needed on tropical feeds to allow the
recommendation of the most useful feedstuffs, and to guide
farmers away from using forages that are of very low nutritional
value.

Many tropical feeds contain toxic substances. Some of the
tropical legumes contain toxic amino acids or alkaloids (eg:
leucaena contains mimosine while cassava contains cyanogens). By
the use of a mixture of forages, the concentration of specific
toxins can be kept to non-hazardous levels. Thus potentially
valuable feeds such as leucaena can be utilized as components of
forage mixtures.

Rabbits can be raised successfully without the use of grain in
the diet. For example, Raharjo et al (1986b) used a diet
in which all of the protein and energy were provided by alfalfa
meal and wheat milling by products, and found that production of
does over several parities was adequate. Because energy and
protein needs are highest for lactation, it might be desirable to
use a concentrate supplement for lactating does, and raise the
weaned rabbits entirely on forage and agricultural by-products
such as wheat bran or rice bran. Rice bran is an excellent energy
source for rabbits (Raharjo 1987), and is available in large
quantities in many developing countries. However, it is
susceptible to development of rancidity, which may reduce
palatability. Care should be taken to avoid rancid rice bran in
rabbit feeding.

The amount of forage offered should be adjusted to be close to
the amount voluntarily consumed. It is desirable to provide fresh
forage at least twice daily, with the uneaten material removed
before additional feed is offered to prevent spoilage. With
palatable forages, the daily intake of fresh forage of a doe or
weaned rabbits will be about 400-500 g per animal per day. The
amount of concentrate offered should be about 50 g per animal per
day. Either a purchased commercial concentrate or a home-mix,
compounded supplement consisting of garden/table refuse may be
used. In addition, rabbits require salt in their diet.

The palatability of forages is important in rabbit production,
particularly in situations when the forages are expected to
provide a major part of the daily nutrient intake. Raharjo and
Cheeke (1985) and Raharjo (1987) evaluated a number of Indonesian
forages in feed preference tests. In general, tropical legumes
were preferred over grasses and agricultural by-products, with
the exception of gliricidia (Gliricidia sepium), a legume
which proved to be unpalatable. Leucaena (Leucaena
leucocephala) is a very palatable feed to rabbits, even
though it contains the toxic amino acid mimosine. Erythrina (Erythrina
lithosperma), another legume, was well accepted. Sweet potato
vines were palatable to rabbits in the study of Raharjo (1987),
while banana and papaya leaves were poorly accepted. Most of the
grasses (eg: Setaria, Brachiaria, elephant grass) were less
palatable than the legumes.

Tree leaves can be used in many areas to provide forage in the
dry season. Besides the tropical legumes previously mentioned,
other trees with potential for feeding include the mulberry (Morus
spp.) which is used in India, Brazil and Costa Rica as a
forage, and black locust (Robinia pseudoacacia), grown
extensively in China for rabbit feed. Ramie is utilized in
Brazil, where it is considered a highly palatable and nutritious
green feed for rabbits.

Much further research is needed on the nutritional and feeding
value of tropical feeds for rabbit production, and the
development of optimal feeding systems. Cheeke (1987) has
summarized the current information available on the nutrition and
feeding of rabbits under temperate and tropical conditions.

Disease control measures

One distinct attribute of rabbit farming is the relatively low
incidence of epidemic diseases when a high standard of hygiene
and careful management is practiced (IFS 1978). Rabbits do not
require routine vaccination or medications to prevent or treat
certain diseases. This is an important aspect since in other
livestock species the lack of proper drugs is sometimes
recognized as a major constraint to successful production.

When a disease does occur local remedies can often be
effectively used as treatment. For example, one common disease
condition referred to as ear mites (caused by an external
parasite, Psoroptes cuniculi) can both be prevented and treated
by applying drops of an oil-kerosene solution directly inside the
ear canal. Vegetable oil, red palm oil and even clean engine oil
may be used. In control of digestive disorders, such as diarrhea
and constipation, various medicinal herbs and greens used in
Cameroonian tribal cultures have been observed to provide similar
therapeutic results in rabbits (Lukefahr and Goldman 1985). Other
diseases or maladies, such as abscesses, cannibalism, skin mange
and warbles, likewise have been inexpensively controlled using
proven local measures.

Owen (1976) observed an apparent trend of lower disease
incidence and/or higher productivity levels in rabbit operations
managed as small-scale family units as opposed to intensive,
commercial units. Management quality per animal may be less in
large operations, and the close confinement situation may also
impose greater likelihood of rapid disease outbreak, particularly
concerning myxomatosis and pasteurellosis. It is imperative,
therefore, where large central rabbit operations exist that
stringent levels of hygiene and culling of diseased animals, as
well as implementing proper quarantine measures, be maintained.

Two diseases of major global concern to rabbit production are
coccidiosis and pasteurellosis. While coccidiosis can largely be
prevented and treated, this disease often goes undiagnosed to the
point where serious physical injury occurs -- liver damage and
severe weight loss. Raising rabbits on the ground aggravates the
problem due to more direct exposure to the infectious agent.
Various sulpha-based drugs have shown good results in controlling
rabbit coccidiosis (Aduma 1978). Sanitation is a critical
determinant in the control of episodic frequency and morbidity
levels due to coccidiosis outbreaks.

Pasteurellosis is a bacterial disease (Pasteurella
multocida) which affects nearly all body tissues. Signs of
the disease include mucopurulent nasal discharge, pneumonia,
dermal abscesses, conjunctivitis, infertility and death. Only
limited success is noted with treatment using broad-spectrum and
sulpha based drugs. Moreover, only a culture test can confirm
definitive exposure to Pasteurella. In well managed rabbit herds,
however, the disease may rarely be a problem. Currently, the best
means of controlling pasteurellosis is achieved through proper
housing design, strict culling of infected animals and/or
selection of healthy stock and quarantine. Some laboratories and
universities have developed specific pathogen-free (SPF) stock
which are pasteurella-free; projects have in some cases
established rabbit populations through SPF stock importations.
General guidelines of rabbit stock importation, with regard to
disease control and sound genetic resource utilization, are
highlighted in Table 4.

Pasteurellosis has been detected in certain rabbit projects in
developing countries where the common opinion of project managers
was that the original imported stock introduced the disease. In
one major rabbit project in China, some rabbits were observed as
having expressed various outward signs (eg: sneezing, nasal
discharge and matted inner forepaws) of a seemingly rare
respiratory disease; a team of veterinarians was perplexed as to
the definitive cause of the disease. A rabbit specialist
consultant later recognized the disease as a classic case of
pasteurellosis (Milne 1982). Unfortunately, this scenario has
repeatedly occurred in several other countries.

A recent paper from China by Xu et al (1988) reported on the
serious outbreak of a new viral disease ("rabbit hemorrhagic
disease virus - RHDV") which has become manifested in parts
of Asia and Europe, and most recently in North America. The body
organs, especially lungs, liver and spleen, are severely
affected. To date, no effective treatment is available since the
immunological mechanism is not understood. Strict quarantine
measures to control further spread of this disease are now
underway (Patton 1989).

Throughout the world - developed and developing - there is a
great need for veterinarians and extension field workers to
become more familiar in the diagnosis, prophylaxis and treatment
of rabbit diseases in regions where rabbit projects or
enterprises exist. There is an urgent need for applied research
in these basic areas of rabbit pathology.

Environmental and housing systems

Like other livestock species, rabbits need protection from
adverse environmental conditions, including protection against
predators. While ample sunlight and ventilation are important,
either of both extremes may well limit production. Air quality is
of major concern in the control of respiratory diseases, such as
pasteurellosis and pneumonia. Ambient temperature and humidity
levels, likewise, are particularly relevant to tropical or arid
environments.

Under controlled experimental regimens, Stephen (1981) and
Poujardieu and Matheron (1984) investigated varying temperature
and humidity stress effects on growth and feeding performances of
rabbit fryers. Stephen (1981) observed optimal productivity at
18°C (as compared with 5 and 30°C) and 70% humidity (compared
with 60 and 80%) of 37.4 g average daily gain and 4.23 feed
efficiency values. Poujardieu and Matheron (1984) reported that
changes in temperature and humidity levels were additive on
growth response, and that there were no compensatory gains due to
previous environmental stress encounters.

It is well established that high ambient temperature can cause
infertility in breeding rabbits, bucks being more sensitive than
does. Rabbits are apparently more adversely affected by hot as
opposed to cold climates. Prolonged exposure to a critical
temperature in excess of 30°C is considered the threshold point
at which infertility may result. A number of practical measures
for alleviating heat stress have been documented by Cheeke et al
(1987). Examples of such measures are providing cool water, ample
shade, evaporative cooling, proper housing design and location,
and usage of young and more potent bucks.

The rabbit's needs for basic shelter to sustain production are
modest. It is fortuitous that the building materials required for
construction of simple sheds, hutches, nest boxes, hay racks, and
feeding and watering equipment are generally abundant in tropical
developing countries. This attribute embellishes the overall low-cost
feasibility of small-scale rabbit farming as an alternative
enterprise (see Table 3 of companion paper by Lukefahr and Cheeke
1990).

Suitable shelter for rabbits might be an outdoor shed, veranda
or empty room of the family compound, or a complete hutch (cage
with roof and siding). Shed designs should be of narrow width
(less than 6 m) with open sides to facilitate natural
ventilation. The run of the shed can be of any length. The height
of the shed can be designed to mimic a chimney effect to provide
cooling through natural air movement (Cheeke et al 1987).
The relative position of the rabbitry site should augment
favorable environmental conditions. Rugh (1978) discussed several
housing systems appropriate to Africa. In semi-desert regions
where wood is scarce or costly, rabbit shelters can be
constructed out of mud and thatch-grass as reported by Owen
(1981). The rabbit dome concept - an underground earthen shelter
which offers relief to high daylight temperatures - has merit in
arid areas (Gentry 1983; Finzi et al 1988). Floor rearing
systems of rabbit production, common to the Near East, however,
are usually associated with increased incidence of parasitism
(eg: coccidiosis) due to direct floor contamination.

Hutches can represent a variety of forms. Examples of durable
and inexpensive building materials include bamboo, raffia palm,
bush sticks, woven wood straps, bricks, mortar, etc., which have
been reported throughout the developing countries (McNitt 1980;
Owen 1981; Cheeke 1983; Lukefahr and Goldman 1985). Basically,
each breeding doe unit requires a cage floor area of less than 1
m5, while each fryer unit requires from 0.05 to 0.10 m5.
Regardless of the construction material used, the hutch should
facilitate a comfortable and clean environment and be under the
direct control of the farmer.

Accessory equipment: hay racks, nest boxes and salt, feeding
and\ watering containers, can be fabricated from a diversity of
products, including refuse items (bottles, cans and tins). Nest
boxes made of wood, clay, metal and basket materials are useful
in accommodating young litters. Generally, the nest boxes should
be supplied with fine-stemmed grass hay, cotton, shredded paper,
wood shavings, or other similar insulatory forms to enhance
litter survival. Feeding and watering equipment must be readily
accessible, voluminous and regularly sanitized. Clean water
should always be available.

Rabbit losses due to predators and thieves can be a common
threat to farmers. Usage of sturdy, well designed hutches, a
protective fence, guard dog, close proximity of the rabbitry to
the compound, installment of noisy items (eg: bells, chimes and
gongs), spring-loaded rodent-traps, locks and native taboo
deterrents are some examples of proven measures of control.

Poujardieu B and Matheron G 1984 Influence
of a hot and wet environment on growth of young does. (in French
with English abstract). Paper in the III World Rabbit Congress,
Rome, April 4-8, pp. 107-118. WRSA